Yesterday I started with OpenGL, but I''ve already lerned a lot. But there are still 3 problems I have to solve:
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1
If I use fog as following:
glFogi(GL_FOG_MODE, GL_LINEAR);
glFogfv(GL_FOG_COLOR, fogColor);
glFogf(GL_FOG_DENSITY, 1.0f);
glHint(GL_FOG_HINT, GL_NICEST);
glFogf(GL_FOG_START, 5.0f);
glFogf(GL_FOG_END, 50.0f);
glEnable(GL_FOG);
fog isn''t starting at 5.0 but it is starting right behind my screen, which is equal to 1.0 in my environment. At a depht of 2.0 all faces/object are completele coverd by fog (which means I can''t see them any more).
What do I do wrong?
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2
I would like to use transparent objects, which can be done by using the Alpha-Value. In order to avoid one object being in front of another (so that I can''t see the one behind, as if the front-object was opage) i should use
glDisable(GL_DEPTH_TEST);
This is really working, as long as I dont use non-transparent objects as well. If I do so, I get rubbish on my screen (of course!).
Is there a way to use both transparent and non-transparent objects at once? Some one said I had to do do a multi-pass-rendering, but I dont know how to do taht, and I think there has to be another solution
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3
My version of the help-file opengl.hlp ist corrupted. It says:
The equation for GL_EXP fog is "error with bitmap-display"
Can somebody tell me the correct equation for GL_LINEAR, GL_EXP and GL_EXP2? The Help-Topic ist named "glFogf, glFogi, glFogfv, glFogiv"